Capacitor structure and method for manufacturing the same

ABSTRACT

A capacitor structure comprises a substrate having a first side and a second side opposite to the first side; a plurality of first trenches formed on the first side of the substrate; a plurality of second trenches formed on the second side of the substrate; a first capacitor extending along the first side and into the first trenches; and a second capacitor extending along the second side and into the second trenches.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates in general to a capacitor structure and a method for manufacturing the same, and more particularly to a deep trench capacitor structure and a method for manufacturing the same.

Description of the Related Art

A capacitor structure plays a critical role in a semiconductor device. In particular, the capacitor structure having a high capacitance is in highly demands. For example, a higher storage capacitance in DRAM can increase its stability; a higher capacitance in a decoupling capacitor can filter more noise. Accordingly, it is urged to develop a capacitor structure having a high capacitance.

SUMMARY OF THE INVENTION

In a comparison example, a capacitor structure may include a deep trench capacitor (DTC) formed on a single side of a substrate. In order to increase the capacitance of the capacitor structure, depths of the trenches for the capacitor are desired to be increased. However, if depths of the trenches for the capacitor are too deep, insulating layer(s) and conductive layer(s) included in the capacitor may not be properly formed in the trenches, and problems of the current leakage or dielectric breakdown may be occurred. Therefore, there is a need for developing a capacitor structure to improve the problems described above.

The present invention is directed to a capacitor structure and a method for manufacturing the capacitor structure.

According to an embodiment of the present invention, a capacitor structure is provided. A capacitor structure comprises a substrate having a first side and a second side opposite to the first side; a plurality of first trenches formed on the first side of the substrate; a plurality of second trenches formed on the second side of the substrate; a first capacitor extending along the first side and into the first trenches; and a second capacitor extending along the second side and into the second trenches.

According to another embodiment of the present invention, a method for manufacturing a capacitor structure is provided. The method comprises: providing a substrate having a first side and a second side opposite to the first side; forming a plurality of first trenches on the first side; forming a first capacitor extending along the first side and into the first trenches; forming a plurality of second trenches on the second side; and forming a second capacitor extending along the second side and into the second trenches.

The above and other aspects of the invention will become better understood with regard to the following detailed description of the preferred but non-limiting embodiment(s). The following description is made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a cross-sectional view illustrating a capacitor structure according to a first embodiment of the present invention.

FIG. 1B is a top view illustrating a plurality of first trenches and a plurality of second trenches in the capacitor structure of FIG. 1.

FIG. 2 is a cross-sectional view illustrating a capacitor structure according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a capacitor structure according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a capacitor structure according to a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a capacitor structure according to a fifth embodiment of the present invention.

FIGS. 6A-6C illustrate a method for manufacturing the capacitor structure according to an embodiment of the present application.

FIG. 7 illustrates the capacitor structure applied in an interposer according to an embodiment of the present application.

FIG. 8 illustrates the capacitor structure applied in an interposer according to another embodiment of the present application.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be noted that the structures, processes, and contents of the embodiments are merely illustrative, and the scope of the present application is not limited to the aspects described. It is to be understood that the present application dose not show all possible embodiments, and is not to be construed as being limited by the scope of the application, and the structure and process of the embodiments may be varied and modified to meet the needs of the application for one of ordinary skill in the art. Therefore, other implementations not presented in this application may also be applicable.

Further, in the embodiments, the same or similar elements are designated by the same or similar reference numerals for clarity. In addition, the drawings have been simplified to clearly illustrate the contents of the embodiments, and the scale ratios in the drawings are not drawn to scale in accordance with the actual products, and thus are not intended to limit the scope of the application.

FIG. 1A is a cross-sectional view illustrating a capacitor structure 10 according to a first embodiment of the present invention. FIG. 1B is a top view illustrating a plurality of first trenches 102 a and a plurality of second trenches 102 b in the capacitor structure 10 of FIG. 1A. FIG. 1A shows a plane formed by a first direction (i.e. X direction) and a third direction (i.e. Z direction) and corresponding to line 1A-1A′ of FIG. 1B. FIG. 1B shows a plane formed by the first direction (i.e. X direction) and a second direction (i.e. Y direction), and the elements formed in/on the first trenches 102 a and the second trenches 102 b are omitted in FIG. 1B.

Referring to FIGS. 1A and 1B, a capacitor structure 10 comprises a substrate 100 having a first side 100 a and a second side 100 b opposite to the first side 100 a; a plurality of first trenches 102 a formed on the first side 100 a of the substrate 100; a plurality of second trenches 102 b formed on the second side 100 b of the substrate 100; a first capacitor 110 a extending along the first side 100 a and into the first trenches 102 a; and a second capacitor 110 b extending along the second side 100 b and into the second trenches 102 b.

As shown in FIG. 1A, the substrate 100 has an upper surface 100U corresponding to the first side 100 a of the substrate 100. As shown in FIG. 1B, the first trenches 102 a are disposed along the first direction (i.e. X direction) and the second direction (i.e. Y direction) on the first side 100 a of the substrate, the first direction and the second direction are intersected with each other and parallel to the upper surface 100U of the substrate 100. That is, the first side 100 a corresponds to the upper surface 1000 of the substrate 100, and the second side 100 b corresponds to a lower surface of the substrate 100. The first trenches 102 a and the second trenches 102 b penetrate portions of the substrate 100 along the third direction (i.e. Z direction). More specifically, the first trenches 102 a extend from an upper surface 1000 of the substrate 100 to the inner portion of the substrate 100, and the second trenches 102 b extend from a lower surface of the substrate 100 to the inner portion of the substrate 100. In some embodiments, the extending directions of the first trenches 102 a and the second trenches 102 b are parallel to the third direction (i.e. Z direction).

In the present embodiment, as shown in FIG. 1A, an angle α formed between a sidewall of the first trench 102 a and a bottom of the first trench 102 a is 90 degrees, and an angle β formed between a sidewall of the second trench 102 b and a bottom of the second trench 102 b is 90 degrees. In other embodiments, the angle α formed between the sidewall of the first trench 102 a and the bottom of the first trench 102 a may be greater than 90 degrees, or/and the angle β formed between the sidewall of the second trench 102 b and the bottom of the second trench 102 b may be greater than 90 degrees, such that the first trench 102 a or/and the second trench 102 b may have a tapered sidewall.

Referring to FIGS. 1A and 1B, the first trenches 102 a and the second trenches 102 b are separated in the third direction (i.e. Z direction), and are alternatively disposed in the substrate 100, such that the first capacitor 110 a formed in the first trenches 102 a and the second capacitor 110 b formed in the second trenches 102 b are alternatively disposed in the substrate 100. In the present embodiment, the first trenches 102 a and the second trenches 102 b are overlapped in the first direction (i.e. X direction), that is, a first depth D1 of each of the first trenches 102 a and a second depth D2 of each of the second trenches 102 b may be greater than half of a thickness of the substrate 100, respectively, but the present application is not limited thereto. In other embodiments, the first trenches 102 a and the second trenches 102 b may be separated in the first direction (i.e. X direction). In some embodiments, the first depth D1 may be equal to the second depth D2.

In some embodiments, referring to FIGS. 1A and 1B, each of the first trenches 102 a and each of the second trenches 102 b may have a first critical dimension CD1 and a second critical dimension CD2 along the first direction (i.e. X direction), respectively. A first pitch P1 may be formed between two neighboring first trenches 102 a along the first direction (i.e. X direction). A second pitch P2 may be formed between two neighboring second trenches 102 b along the first direction (i.e. X direction). An aspect ratio of the first trenches 102 a of the first critical dimension CD1 to the first depth D1 (CD1:D1) may be equal to or smaller than 1:15, for example, CD1:D1=1:10. An aspect ratio of the second trenches 102 b of the second critical dimension CD2 to the second depth D2 (CD2:D2) may be equal to or smaller than 1:15, for example, CD2:D2=1:10. A ratio of the first critical dimension CD1 to the first pitch P1 may be equal to or greater than 1:2.2, for example, CD1:P1=1:3. A ratio of the second critical dimension CD2 to the second pitch P2 may be equal to or greater than 1:2.2, for example, CD2:P2=1:3.

As shown in FIG. 1A, a first insulating film 104 a extends along the first side 100 a and into the first trenches 102 a and a second insulating film 104 b extends along the second side 100 b and into the second trenches 102 b. The first insulating film 104 a is formed between the substrate 100 and the first capacitor 110 a. The second insulating film 104 b is formed between the substrate 100 and the second capacitor 110 b. That is, portions of the upper surface 1000 of the substrate 100, the sidewalls of the first trenches 102 a and the bottoms of the first trenches 102 a are covered by the first insulating film 104 a and the first capacitor 110 a, and portions of the lower surface of the substrate 100, the sidewalls of the second trenches 102 b and the bottoms of the second trenches 102 b are covered by the second insulating film 104 b and the second capacitor 110 a. In the present embodiment, the first capacitor 110 a comprises a first conductive layer 111 a, a first dielectric layer 113 a, a second conductive layer 115 a, a second dielectric layer 117 a and a third conductive layer 119 a sequentially stacked on the first side 110 a of the substrate 100 and into the first trenches 102 a; and the second capacitor 110 b comprises a first conductive layer 111 b, a first dielectric layer 113 b, a second conductive layer 115 b, a second dielectric layer 117 b and a third conductive layer 119 b sequentially stacked on the second side 110 b of the substrate 100 and into the second trenches 102 b. The first capacitor 110 a and the second capacitor 110 b include a “MIMIM (metal-insulator-metal-insulator-metal)” structure, respectively. However, the amounts of the dielectric layer(s) and the conductive layers in the first capacitor 110 a and the second capacitor are not limited thereto.

In the present embodiment, the first trenches 102 a are disposed in a first region A1 on the first side 100 a of the substrate 100, and the second trenches 102 b are disposed in a second region B1 on the second side 100 b of the substrate 100. The first region A1 corresponds to the second region B1; in other words, the first region A1 and the second region B1 are overlapped in the third direction (i.e. Z direction), but the present invention is not limited thereto.

In some embodiments, the substrate 100 may be a silicon-based substrate. The first conductive layers 111 a and 111 b, the second conductive layers 115 a and 115 b and the third conductive layers 119 a and 119 b may include a material formed of copper, titanium nitride (TiN) or any other suitable conductive materials. The first dielectric layers 113 a and 113 b and the second dielectric layers 117 a and 117 b may include a material formed of the thermal oxide, oxide-nitride-oxide (ONO) composite film or other suitable dielectric materials.

In some embodiments, the substrate 100 may be applied in an interposer, a Silicon on Insulator (SOI) wafer or other suitable substrate. In some embodiments, the substrate 100 may have a thickness in a range of 50-100 μm along the third direction (i.e. Z direction), but the present application is not limited thereto.

In some embodiments, the first capacitor 110 a and the second capacitor 110 b may be electrically connected to different elements/devices. In some embodiments, the first capacitor 110 a and the second capacitor 110 b may be electrically connected together as one capacitor, for example, by the through silicon via (TSV), as shown in FIG. 7.

In a first comparative example, a capacitor structure has only a first capacitor formed on a single side of a substrate and formed into first trenches, the other side of the substrate has no trenches and the capacitor, and the pitch, the depth, and the critical dimension of the first trenches are respectively the same as the pitch, the depth, and the critical dimension of the first trenches 102 a shown in FIG. 1A of the present invention.

Since the capacitor structure 10 of the present invention has double-sided deep trench capacitors (capacitors 110 a and 110 b), the surface area of the capacitors 110 a and 110 b in the present invention is higher than the surface area of the capacitor in the first comparative example having the single-sided deep trench capacitor, the capacitor structure 10 of the present invention may have higher capacitance (such as 1.7 times). If the capacitance of the capacitor structure in the first comparative example is desired to achieve the capacitance of the capacitor structure in the present invention, a depth of the first trenches has to be increased (such as 21 μm) and a pitch of the first trenches has to be decreased (such as 2 μm), such that the process window and the process cost have to be increased; the aspect ratio of the first trenches may be too high (such as 1:21) and the critical dimension to the pitch may be too low (such as 1:2), the dielectric layers and the conductive layers of the capacitor in the first trenches may not be properly formed, thereby increasing the risk of current leakage or dielectric breakdown. Further, the process for forming the first capacitor and the second capacitor may be identical or similar, so that the process for forming the capacitor structure 10 is simple. Accordingly, the capacitor structure 10 according to an embodiment of the present invention may achieve a higher capacitance in a low process cost while maintaining a good electrical property without sacrificing process window and can also avoid process complexity.

FIG. 2 is a cross-sectional view illustrating a capacitor structure 20 according to a second embodiment of the present invention, and shows a plane formed by the first direction (i.e. X direction) and the third direction (i.e. Z direction). The configuration of the capacitor structure 20 and the configuration of the capacitor structure 10 shown in FIG. 1 are similar, and the difference between the capacitor structure 20 and the capacitor structure 10 is in that the depths of the first trenches 202 a and the second trenches 202 b are smaller than the depths of the first trenches 102 a and the second trenches 102 b, and the identical/similar features are not repeated here.

Referring to FIG. 2, the first trenches 202 a and the second trenches 202 b are separated in the third direction (i.e. Z direction), and are separated in the first direction (i.e. X direction). In the present embodiment, a gap G1 may be formed between the first trenches 202 a and the second trenches 202 b projected on a plane perpendicular to the upper surface 1000 of the substrate 100. In other embodiments, there may be no gap between the first trenches 202 a and the second trenches 202 b projected on a plane perpendicular to the upper surface 1000 of the substrate 100; the bottoms of the first trenches 202 a and the bottoms of the second trenches 202 b may be aligned along the first direction (i.e. X direction). A first insulating film 204 a and a first capacitor 210 a comprising a first conductive layer 211 a, a first dielectric layer 213 a, a second conductive layer 215 a, a second dielectric layer 217 a and a third conductive layer 219 a extend along the first side 100 a and into the first trenches 102 a; a second insulating film 204 b and a second capacitor 210 a comprising a first conductive layer 211 b, a first dielectric layer 213 b, a second conductive layer 215 b, a second dielectric layer 217 b and a third conductive layer 219 b extend along the second side 100 b and into the second trenches 202 b. The materials and properties of the first insulating film 204 a, the first capacitor 210 a, the second insulating film 204 b and the second capacitor 210 b are respectively identical or similar to the materials and properties of the first insulating film 104 a, the first capacitor 110 a, the second insulating film 104 b and the second capacitor 110 b.

In the present embodiment, the first trenches 202 a and the second trenches 202 b are disposed in a first region A2 on the first side 100 a of the substrate 100 and a second region B2 on the second side 100 b of the substrate 100, respectively, and the first region A2 and the second region B2 are overlapped in the third direction (i.e. Z direction), but the present invention is not limited thereto.

FIG. 3 is a cross-sectional view illustrating a capacitor structure 30 according to a third embodiment of the present invention, and shows a plane formed by the first direction (i.e. X direction) and the third direction (i.e. Z direction). The difference between the capacitor structure 30 and the capacitor structure 10 is in that the depths of the first trenches 302 a and the second trenches 302 b are smaller than the depths of the first trenches 102 a and the second trenches 102 b; the arrangement of the first trenches 302 a and the second trenches 302 b and the arrangement of the first trenches 102 a and the second trenches 102 b are different; the identical/similar features are not repeated here.

Referring to FIG. 3, the first trenches 302 a and the second trenches 302 b are separated in the first direction (i.e. X direction), and are overlapped in the third direction (i.e. Z direction). In the present embodiment, a gap G3 may be formed between the first trenches 302 a and the second trenches 302 b projected on a plane perpendicular to the upper surface 1000 of the substrate 100. A first insulating film 304 a and a first capacitor 310 a comprising a first conductive layer 311 a, a first dielectric layer 313 a, a second conductive layer 315 a, a second dielectric layer 317 a and a third conductive layer 319 a extend along the first side 100 a and into the first trenches 302 a; a second insulating film 304 b and a second capacitor 310 a comprising a first conductive layer 311 b, a first dielectric layer 313 b, a second conductive layer 315 b, a second dielectric layer 317 b and a third conductive layer 319 b extend along the second side 100 b and into the second trenches 302 b. The materials and properties of the first insulating film 304 a, the first capacitor 310 a, the second insulating film 304 b and the second capacitor 310 b are respectively identical or similar to the materials and properties of the first insulating film 104 a, the first capacitor 110 a, the second insulating film 104 b and the second capacitor 110 b.

In the present embodiment, the first trenches 302 a and the second trenches 302 b are disposed in a first region A3 on the first side 100 a of the substrate 100 and a second region B3 on the second side 100 b of the substrate 100, respectively, and the first region A3 and the second region B3 are overlapped in the third direction (i.e. Z direction), but the present invention is not limited thereto.

FIG. 4 is a cross-sectional view illustrating a capacitor structure 40 according to a fourth embodiment of the present invention, and shows a plane formed by the first direction (i.e. X direction) and the third direction (i.e. Z direction). The arrangement of the first trenches 402 a and the second trenches 402 b in the capacitor structure 40 and the arrangement of the first trenches 102 a and the second trenches 102 b in the capacitor structure 10 are different, and the identical/similar features are not repeated here.

Referring to FIG. 4, a first insulating film 404 a and a first capacitor 410 a comprising a first conductive layer 411 a, a first dielectric layer 413 a, a second conductive layer 415 a, a second dielectric layer 417 a and a third conductive layer 419 a extend along the first side 100 a and into the first trenches 402 a; a second insulating film 404 b and a second capacitor 410 b comprising a first conductive layer 411 b, a first dielectric layer 413 b, a second conductive layer 415 b, a second dielectric layer 417 b and a third conductive layer 419 b extend along the second side 100 b and into the second trenches 402 b. The materials and properties of the first insulating film 404 a, the first capacitor 410 a, the second insulating film 404 b and the second capacitor 410 b are respectively identical or similar to the materials and properties of the first insulating film 104 a, the first capacitor 110 a, the second insulating film 104 b and the second capacitor 110 b.

In the present embodiment, the first trenches 402 a are disposed in a first region A4 on the first side 100 a of the substrate 100, and the second trenches 402 b are disposed in a second region B4 on the second side 100 b of the substrate 100, and the first region A4 and the second region B4 are separated from each other in the third direction (i.e. Z direction). The first trenches 402 a and the second trenches 402 b are overlapped in the first direction (i.e. X direction).

FIG. 5 is a cross-sectional view illustrating a capacitor structure 50 according to a fifth embodiment of the present invention, and shows a plane formed by the first direction (i.e. X direction) and the third direction (i.e. Z direction). The depths of the first trenches 402 a and the second trenches 402 b in capacitor structure 50 are smaller than the depths of the first trenches 102 a and the second trenches 102 b in capacitor structure 10; the arrangement of the first trenches 402 a and the second trenches 402 b are different from the arrangement of the first trenches 102 a and the second trenches 102 b, and the identical/similar features are not repeated here.

Referring to FIG. 5, a first insulating film 504 a and a first capacitor 510 a comprising a first conductive layer 511 a, a first dielectric layer 513 a, a second conductive layer 515 a, a second dielectric layer 517 a and a third conductive layer 519 a extend along the first side 100 a and into the first trenches 502 a; a second insulating film 504 b and a second capacitor 510 a comprising a first conductive layer 511 b, a first dielectric layer 513 b, a second conductive layer 515 b, a second dielectric layer 517 b and a third conductive layer 519 b extend along the second side 100 b and into the second trenches 502 b. The materials and properties of the first insulating film 504 a, the first capacitor 510 a, the second insulating film 504 b and the second capacitor 510 b are respectively identical or similar to the materials and properties of the first insulating film 104 a, the first capacitor 110 a, the second insulating film 104 b and the second capacitor 110 b.

In the present embodiment, the first trenches 502 a and the second trenches 502 b are disposed in a first region A5 and a second region B5 of the substrate 100, respectively, and the first region A5 and the second region B5 are separated in the third direction (i.e. Z direction). The first trenches 502 a and the second trenches 502 b are also separated in the third direction (i.e. Z direction). The first trenches 502 a and the second trenches 502 b are separated in the first direction (i.e. X direction). A gap G5 may be formed between the first trenches 502 a and the second trenches 502 b projected on a plane perpendicular to the upper surface 1000 of the substrate 100. In other embodiments, there is no gap formed between the first trenches 502 a and the second trenches 502 b projected on a plane perpendicular to the upper surface 100U of the substrate 100.

FIGS. 6A-6C illustrate a method for manufacturing the capacitor structure 10 according to an embodiment of the present application. The capacitor structure 10 may be manufactured according to the following steps, but the invention is not limited thereto. Other capacitor structures 20-50 may be manufactured by a method similar to the method for manufacturing the capacitor structure 10.

Referring to FIG. 6A, a substrate 100 is provided. The substrate 100 has a first side 100 a and a second side 100 b opposite to the first side 100 a. The substrate 100 may be applied in an interposer, a Silicon on Insulator (SOI) wafer or other suitable substrate. Then, a plurality of first trenches 102 a are formed on the first side 100 a. The first trenches 102 a are disposed along a first direction (X direction) and a second direction (Y direction) on the first side 100 a of the substrate 100. Each of the first trenches 102 a penetrates a portion of the substrate 100, and extends from an upper surface 1000 of the substrate 100 into the inner portion of the substrate 100 along the third direction (i.e. Z direction). In the present embodiment, an angle α formed between a sidewall of the first trench 102 a and a bottom of the first trench 102 a is 90 degrees. In other embodiments, the angle α formed between the sidewall of the first trench 102 a and the bottom of the first trench 102 a may be greater than 90 degrees, such that the first trench 102 a may have a tapered sidewall.

Referring to FIG. 6B, a first insulating film 104 a and a first capacitor 110 a comprising a first conductive layer 111 a, a first dielectric layer 113 a, a second conductive layer 115 a, a second dielectric layer 117 a and a third conductive layer 119 a are formed extending along the first side 110 a of the substrate 100 and into the first trenches 102 a. For example, the first insulating film 104 a, the first conductive layer 111 a, the first dielectric layer 113 a, the second conductive layer 115 a, the second dielectric layer 117 a and the third conductive layer 119 a are sequentially deposited on the first side 110 a of the substrate 100 and into the first trenches 102 a.

Referring to FIG. 6C, a plurality of second trenches 102 b are formed on the second side 100 b. Each of the second trenches 102 b penetrates a portion of the substrate 100, and extends from a bottom surface of the substrate 100 into the inner portion of the substrate 100 along the third direction (i.e. Z direction). In the present embodiment, an angle β formed between a sidewall of the second trench 102 b and a bottom of the second trench 102 b is 90 degrees. In other embodiments, the angle β formed between the sidewall of the second trench 102 b and the bottom of the second trench 102 b may be greater than 90 degrees, such that the second trench 102 b may have a tapered sidewall.

Afterwards, referring back to FIG. 1A, a second insulating film 104 b and a second capacitor 110 b comprising a first conductive layer 111 b, a first dielectric layer 113 b, a second conductive layer 115 b, a second dielectric layer 117 b and a third conductive layer 119 b are formed extending along the second side 110 b of the substrate 100 and into the second trenches 102 b. For example, the second insulating film 104 b, the first conductive layer 111 b, the first dielectric layer 113 b, the second conductive layer 115 b, the second dielectric layer 117 b and the third conductive layer 119 b are sequentially deposited on the second side 110 b of the substrate 100 and into the second trenches 102 b. In this way, the capacitor structure 10 having double-sided deep trench capacitors (first capacitor 110 a and second capacitor 110 b) is formed.

FIG. 7 illustrates the capacitor structure 10 applied in an interposer according to an embodiment of the present application.

Referring to FIG. 7, a first via V1 and a second via V2 penetrate through the substrate 100 along the third direction, respectively. The first capacitor 110 a comprises a first conductive layer 111 a, a first dielectric layer 113 a, a second conductive layer 115 a, a second dielectric layer 117 a and a third conductive layer 119 a sequentially stacked on the first side of the substrate, the second capacitor 110 b comprises a first conductive layer 111 b, a first dielectric layer 113 b, a second conductive layer 115 b, a second dielectric layer 117 b and a third conductive layer 119 b sequentially stacked on the second side 110 b of the substrate 100. That is, the first capacitor 110 a and the second capacitor 110 b include a “MIMIM (metal-insulator-metal-insulator-metal) structure”, respectively. The first insulating film 104 a and the first capacitor 110 a extend along the first side 100 a and into the first trenches 102 a. The second insulating film 104 b and the second capacitor 110 b extend along the second side 100 b and into the second trenches 102 b. The first conductive layer 111 a of the first capacitor 110 a, the first conductive layer 111 b of the second capacitor 110 b, the third conductive layer 119 a of the first capacitor 110 a and the third conductive layer 119 b of the second capacitor 110 b are electrically connected to the first via V1; the second conductive layer 115 a of the first capacitor 110 a, the second conductive layer 115 b of the second capacitor 110 b are electrically connected to the second via V2, such that the first capacitor 110 a and the second capacitor 110 b are electrically connected to each other as one capacitor through the first via V1 and the second via V2.

FIG. 8 illustrates the capacitor structure 10′ applied in an interposer according to another embodiment of the present application. The difference between the capacitor structure 10′ and 10 is in that the structure of the first capacitor 110 a′ and the second capacitor 110 b′ are different from the structure of the first capacitor 110 a and the second capacitor 110 b.

Referring to FIG. 8, a first via V1 and a second via V2 penetrate through the substrate 100 along the third direction, respectively. The first capacitor 110 a′ comprises a first conductive layer 111 a, a first dielectric layer 113 a and a second conductive layer 115 a sequentially stacked on the first side 100 a of the substrate 100, the second capacitor 110 b′ comprises a first conductive layer 111 b, a first dielectric layer 113 b and a second conductive layer 115 b sequentially stacked on the second side 100 b of the substrate 100. That is, the first capacitor 110 a′ and the second capacitor 110 b′ include a “MIM (metal-insulator-metal) structure”, respectively. The first insulating film 104 a and the first capacitor 110 a′ extend along the first side 100 a and into the first trenches 102 a. The second insulating film 104 b and the second capacitor 110 b′ extend along the second side 100 b and into the second trenches 102 b. The first conductive layer 111 a of the first capacitor 110 a′, the first conductive layer 111 b of the second capacitor 110 b′ are electrically connected to a first via V1; the second conductive layer 115 a of the first capacitor 110 a′, the second conductive layer 115 b of the second capacitor 110 b′ are electrically connected to a second via V2, such that the first capacitor 110 a′ and the second capacitor′ 110 b are electrically connected together as one capacitor through the first via V1 and the second via V2.

In sum, the present invention provides a capacitor structure and a method for manufacturing the capacitor structure. According to one embodiment of the present invention, a capacitor structure comprises a substrate having a first side and a second side opposite to the first side; a plurality of first trenches formed on the first side of the substrate; a plurality of second trenches formed on the second side of the substrate; a first capacitor extending along the first side and into the first trenches; and a second capacitor extending along the second side and into the second trenches.

Since the capacitor structure of the present invention has double-sided deep trench capacitors (i.e. first capacitor and the second capacitor), the surface area of the capacitors in the present invention is higher than the surface area of the capacitor in a comparative example having the single-sided deep trench capacitor, and the capacitor structure of the present invention may have higher capacitance. Further, the high capacitance of the present application can be achieved without making the first trenches and the second trenches too deep, so that the risk of current leakage or dielectric breakdown in the capacitor may be decreased. Additionally, the process for forming the first capacitor and the second capacitor may be identical or similar, so that the process for forming the capacitor structure of the present invention is simple. Accordingly, the capacitor structure according to an embodiment of the present invention may achieve a higher capacitance in a low process cost while maintaining a good electrical property without sacrificing process window and can also avoid process complexity.

While the invention has been described by way of example and in terms of the preferred embodiment(s), it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures. 

What is claimed is:
 1. A capacitor structure, comprising: a substrate having a first side and a second side opposite to the first side; a plurality of first trenches formed on the first side of the substrate; a plurality of second trenches formed on the second side of the substrate; a first capacitor extending along the first side and into the first trenches; and a second capacitor extending along the second side and into the second trenches.
 2. The capacitor structure according to claim 1, wherein the substrate has an upper surface corresponding to the first side of the substrate, wherein the first trenches are disposed along a first direction and a second direction on the first side of the substrate, the first direction and the second direction are intersected with each other and parallel to the upper surface of the substrate, wherein the first trenches penetrate the substrate along a third direction intersected with the first direction and the second direction, and the second trenches penetrate the substrate along the third direction.
 3. The capacitor structure according to claim 2, wherein the first trenches and the second trenches are overlapped in the first direction.
 4. The capacitor structure according to claim 3, wherein the first trenches and the second trenches are separated in the third direction.
 5. The capacitor structure according to claim 3, wherein the first trenches are disposed in a first region on the first side of the substrate, the second trenches are disposed in a second region on the second side of the substrate, and the first region corresponds to the second region.
 6. The capacitor structure according to claim 3, wherein the first trenches are disposed in a first region on the first side of the substrate, the second trenches are disposed in a second region on the second side of the substrate, and the first region and the second region are separated from each other in the third direction.
 7. The capacitor structure according to claim 2, wherein the first trenches and the second trenches are separated in the first direction.
 8. The capacitor structure according to claim 7, wherein the first trenches and the second trenches are separated in the third direction.
 9. The capacitor structure according to claim 7, wherein the first trenches and the second trenches are overlapped in the third direction.
 10. The capacitor structure according to claim 7, wherein the first trenches are disposed in a first region on the first side of the substrate, the second trenches are disposed in a second region on the second side of the substrate, and the first region corresponds to the second region.
 11. The capacitor structure according to claim 7, wherein the first trenches are disposed in a first region on the first side of the substrate, the second trenches are disposed in a second region on the second side of the substrate, and the first region and the second region are separated from each other in the third direction.
 12. The capacitor structure according to claim 2, further comprising a first via and a second via penetrating through the substrate, respectively, wherein the first capacitor and the second capacitor are electrically connected to each other through the first via and the second via.
 13. The capacitor structure according to claim 12, wherein the first capacitor comprises a first conductive layer, a first dielectric layer, a second conductive layer, a second dielectric layer and a third conductive layer sequentially stacked on the first side of the substrate, the second capacitor comprises a first conductive layer, a first dielectric layer, a second conductive layer, a second dielectric layer and a third conductive layer sequentially stacked on the second side of the substrate, wherein the first conductive layer of the first capacitor, the first conductive layer of the second capacitor, the third conductive layer of the first capacitor and the third conductive layer of the second capacitor are electrically connected to the first via; the second conductive layer of the first capacitor and the second conductive layer of the second capacitor are electrically connected to the second via.
 14. The capacitor structure according to claim 12, wherein the first capacitor comprises a first conductive layer, a first dielectric layer and a second conductive layer sequentially stacked on the first side of the substrate, the second capacitor comprises a first conductive layer, a first dielectric layer and a second conductive layer sequentially stacked on the second side of the substrate, wherein the first conductive layer of the first capacitor and the first conductive layer of the second capacitor are electrically connected to the first via; the second conductive layer of the first capacitor and the second conductive layer of the second capacitor are electrically connected to the second via.
 15. A method for manufacturing a capacitor structure: providing a substrate having a first side and a second side opposite to the first side; forming a plurality of first trenches on the first side; forming a first capacitor extending along the first side and into the first trenches; forming a plurality of second trenches on the second side; and forming a second capacitor extending along the second side and into the second trenches.
 16. The method according to claim 15, wherein the substrate has an upper surface corresponding to the first side of the substrate, wherein the first trenches are disposed along a first direction and a second direction on the first side of the substrate, the first direction and the second direction are intersected with each other and parallel to the upper surface of the substrate, wherein the first trenches penetrate the substrate along a third direction intersected with the first direction and the second direction, and the second trenches penetrate the substrate along the third direction.
 17. The method according to claim 16, wherein the first trenches and the second trenches are overlapped in the first direction.
 18. The method according to claim 17, wherein the first trenches and the second trenches are separated in the third direction.
 19. The method according to claim 16, wherein the first trenches and the second trenches are separated in the first direction.
 20. The method according to claim 19, wherein the first trenches and the second trenches are separated in the third direction. 